Identifying empty lines of text

[Bob Sneidar]

I have a simple function which will return a string with all non-allowed characters stripped from it. 

function cleanASCII pString, pModeList, pCustomList
   /*
   pModeList is a comma delimited list that may contain the following values:
   "lowercase,uppercase,numbers,tabs,newlines,returns,spaces,symbols,custom"
   If custom is used, then a third paramaeter containing allowed characters must be supplied. 
   */
   if pModeList is empty then
      put " 0-9a-zA-Z" into tAllowedChars
   end if
   
   repeat for each item pMode in pModeList
      put word 1 of pMode into pMode
      
      switch
            break
         case "tabs" is in pMode
            put "\t" after tAllowedChars
            break
         case "newlines" is in pMode
            put "\n" before tAllowedChars
            break
         case "returns" is in pMode
            put "\r" before tAllowedChars -- currently not working
            break
         case "spaces" is in pMode
            put " " after tAllowedChars
            break
         case "numbers" is in pMode
            put "0-9" after tAllowedChars
            break
         case "lowercase" is in pMode
            put "a-z" after tAllowedChars
            break
         case "uppercase" is in pMode
            put "A-Z" after tAllowedChars
            break
         case "symbols" is in pMode
            put "!#$%&'()*+,./:;<=>?@[\\_`{|}~^-" after tAllowedChars
            break
         case pMode is "custom"
            put pCustomList after tAllowedChars
            break
      end switch
   end repeat
   
   put "[" & tAllowedChars & "]" into tMatchText
   
   repeat for each character  theChar in pString
      if matchtext(theChar, tMatchText) is true then
         put theChar after cleanString
      end if
   end repeat
   
   return cleanString
end cleanASCII

Bob S


> On Jan 12, 2018, at 16:48 , David Epstein via use-livecode <use-livecode at lists.runrev.com> wrote:
> 
> I use “the number of words in myString = 0” to test whether a line of text appears empty, since I want a line with only space characters to be understood as empty.
> But a line of text I pasted from elsewhere contained an invisible character whose charToNum value is 202, and this was counted as a word by my script.
> Is there a better way to test for a line of text that has no visible characters?
> Many thanks.
> 
> David Epstein